How long has this been going on? When you were having a period did you use tampons? You have a lot of symptoms for TSS but 6 months is way to long for thos symptoms to be coming up now. If I were you I would make an appointment and see my doctor, especially with the breathing problems and fever.
Believe it or not spotting brown discharge and a little blood ,cramps, lower back pain can all be contributed to a period you were supposed to have but your body decided not to have. Are you really thin and very active, sometimes athletes will stop altogether, my niece did.
But you should still see your doctor, a lot of the other symptoms should be looked at , or considered together to figure out what is going on with you. Good luck